A change in the demand for commodity Y due to a change in the price of commodity X is termed as:

Consider the following statements regarding the dynamics of consumer demand: Statement 1: Expansion of demand is characterized by a downward movement along an existing demand curve resulting specifically from a decrease in the price of the commodity. Statement 2: An increase in demand is represented by a rightward shift of the entire demand curve driven by non-price factors such as rising consumer income or changing preferences. Which of the following options is correct?

According to economic theory, demand curves typically have a negative slope primarily because: